Three-dimensional holograms are eye-catching. They are useful in advertising almost any goods. For example, holograms can be incorporated into sports trading cards, inserts for CDs, on the face of tickets to verify authenticity or even on mouse pads used with computer pointing devices. However, holograms typically involve difficult photographic techniques that increase the price for the images. Thus, it is not presently economical to use holograms on many items. A need exists for a less expensive method of generating an image similar to a hologram. Such a method should create both three dimensional imagery or action sequences that move according to the viewing angle.
One method of creating an image is disclosed in U.S. Pat. No. 5,364,274 to Sekiguchi entitled "Process For Producing A Display With Movable Images." The Sekiguchi process involves generating at least two images with a computer. The first can be produced either by creating an original illustration or by scanning a desired image. The second image can be generated by electronically copying and subsequently altering and modifying the first image on the monitor. At least one and preferably all the images are then masked, electronically removing, erasing, canceling, or otherwise deleting a symmetrical pattern of spaces on the images to form masked images with a spaced array of stripes comprising viewable opaque portions with spaces positioned between and separating the stripes. After masking, part of the masked image is overlayed, superimposed and combined upon each other in offset relationship so that the viewable strips of one image are positioned in the spaces of another image. The superimposed images are printed on an underlying web. A grid or sleeve can be placed in front of the superimposed images of the rearward web. Thus, the grid will reveal one image when positioned over the printed portions of the other constituents of the combined pattern. Movement of the grid will then reveal another image. The Sekiguchi method does not disclose dithering of the superimposed images prior to printing the image on an output devices.
Another method of creating a lenticular image is disclosed in U.S. Pat. No. 5,494,445 to Sekiguchi et al. entitled, "Process and Display with Movable Images." This patent is a continuation-in-part of the Sekiguchi '274 patent. Another method of creating a lenticular image is disclosed in U.S. Pat. No. 5,695,346 to Sekiguchi et al. entitled, "Process and Display with Movable Images." This patent is a continuation-in-part of the Sekiguchi et al. '445 patent. Neither of the Sekiguchi et al. patents disclose a method of producing a lenticular image wherein the interlaced image is dithered one or more times, neither do they disclose the sizing of the dithered interlaced image in order to match the frequency of the combined image strips to the frequency of the lenticules on a lenticular lens.
Another method of producing an image is disclosed in U.S. Reissue Pat. No. 35,029 to Sandor et al. entitled "Computer Generated Autostereography Method and Apparatus." The Sandor method produces an autostereographic image by inputting to a computer a predetermined number of planar images of an object. Each of the planar images is a view of an object from a different viewpoint. The computer then interleaves the images and then prints these onto a film. A spacer with a thickness is placed over the film. Finally a barrier strip having slits is placed over that spacer. The system requires the use of an off-axis projection to produce the three-dimensional image. If the image is to be viewed from a position (x,y,z) in front of the autostereograph, then a position (x',y',z') is determined on the film that will make that projection. The Sandor et al. '029 Patent does not disclose dithering of the interlaced image.
U.S. Pat. Nos. 5,311,329 and 5,438,429 both to Haeberli et al. disclose a method for the digital filtering of lenticular images wherein the method is similar to that of the Sandor et al. U.S. Pat. No. 5,113,213, but further includes a step of unsharp masking which is a technique employed to increase the sharpness of edges in a lenticular image. The unsharp masking technique requires a measurement of intensities of pixels in an interlaced image and in an unfocused or blurred version of the same interlaced image. Once the waveform intensities have been determined, the intensity of each pixel is adjusted either up or down according to a calculated blending factor. Neither of the Haeberli et al. patents disclose dithering of the interlaced image either once or twice after the interlaced image has been formed, nor do they disclose the sizing of the dithered interlaced image such that the frequency of combined image strips in the interlaced image will substantially match the lenticular frequency of a lenticular lens and the resolution of the sized interlaced image will substantially match or exceed the resolution of an output device used to output the interlaced image.
Substrates bearing interlaced images in combination with lenticular lenses overlaying the interlaced images are also disclosed in U.S. Pat. No. 5,488,451 to Goggins, U.S. Pat. No. 5,568,313 to Steenblik et al., U.S. Pat. No. 5,543,964 to Taylor et al., U.S. Pat. No. 5,461,495 to Steenblik et al., U.S. Pat. No. 4,935,335 to Fotland, U.S. Pat. No. 4,082,433 to Appledorn et al., U.S. Pat. No. 3,937,565 to Alasia, U.S. Pat. No. 3,538,632 to Anderson, and U.S. Pat. No. 3,119,195 to Braunhut.
Known processes for preparing lenticular items generally require prefabrication of the lenticular lens and printing of an interlaced image on a substrate. During manufacture, the lenticular frequency of the lenticular lens can differ from specifications as the lens is being produced or can vary from batch to batch. If the lenticular lens has a frequency that varies across the lens, it is incorrectly manufactured. Consistency and uniformity are essential to the function of quality lenticular lenses. The variation in lenticular frequency makes matching of it with the interlaced image strip frequency and resolution difficult. Therefore a need exists for a method of preparing lenticular items where the frequency of the interlaced image can be made to substantially match to the lenticular frequency of the lenticular lens as desired.
In the known art, source images are interlaced with at least one pixel per image stripe at a pixel resolution that approximates the product of the lenticular frequency times the number of source images. This initial interlaced or masked image has a one to one relationship of pixel to image stripe. The prior art also discloses use of a barrier image instead of a lenticular lens which allows the prior art to define the barrier/mask using a one to one pixel relationship between the interlaced image stripes, the barrier stripes and the printer resolution. With a lenticular lens this is not always possible since most printers have fixed resolutions. If the initial interlaced image is printed on a device that does not support the pixel resolution of the interlaced image the output device will compensate for the difference using various dithering and interpolation methods. Usually this will result in an undesirable banding effect as the printer tries to compensate for the resolution difference.
A further need exists for a method which produces high-quality, inexpensive, and easily constructed images similar to holograms. The method should allow for the use of any quality of input. Further, it should allow for the production of the output image with any quality of output device. The method should eliminate unnecessary elements, thereby reducing the cost of the finished image.